Channel Gradient as a Factor in the Distribution of Beaver Dams and Ponds on Small Rivers: A Case Study in the Northern Extremity of the Volga Upland, the East European Plain

A very noticeable increase in the beaver population (mainly Eurasian (Castor fiber L.)) East European Plain since end of 20th century through reintroduction contributed to emergence a large number dams and ponds, which resulted transformation channels hydrological regime small rivers. In this paper, for first time Middle Volga region, regularities distribution ponds on rivers were revealed based topographic survey river channel, regulated by activity recent decades. The materials paper obtained during field (geodetic) work August September 2022 valleys two typical north Upland, Morkváshinka River (16.6 km) Morkváshka (7.8 km), with subsequent statistical processing. According results obtained, all we encountered located sections their relatively (up 1%) medium (1–3%) average gradients. upper reaches rivers, expansion is limited gradients channels. Along entire length, there an alternation sectors “natural” (not beavers) channel cascade ponds. Drained (at survey) without dams, as well those preserved destroyed also identified River. On whole, 26–48% length studied has been transformed activity. per kilometer watercourse 3.7–5.1. most favorable are 3.6–16.6 m/km, or 0.36–1.66%. gradient above no related found these 30 3%. An upstream reflected size slightly larger than channel.